io.github.syncday-app/sync-day
REMOTE · SYNC.DAY
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Available components
Last scanned (1 day ago)
Scores higher than 79% of remote servers
Reachable. Last reached 4 Nov 2026.
Category Productivity and Notes
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (remove_participant). See how to fix → View diagnostics → Fail
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability66
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 2091 tokens (~261/item across 8 items; 8 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.Pass
- An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 7 Oct 26 0
- Stability: 0.97 → pass security
- 4 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.
- 2 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 87 to 90. That category is still filling its 30-day observation window: 26 days of observed history at the previous scan, 27 at this one. The score rises as the window fills, whether or not the server changes.
- 28 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 6 Sept 26 0
- Stability: unverified → 0.03 ▲ functional
- 5 Sept 26 0
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 4 Nov 2026 · Probed https://sync.day/mcp/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=*.sync.day | CN=YR1,O=Let's Encrypt,C=US | 1 Nov 2026 | 30 Jan 2027 | RSA 2048 | SHA256-RSA | 5caf43965898c295a45dd79f8ad1a9ee4d1 |
| SANs: *.sync.day, sync.day | ||||||
| CN=YR1,O=Let's Encrypt,C=US (CA) | CN=Root YR,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | RSA 2048 | SHA256-RSA | a20253f15f2691c05dc1ce13b9bcca4e |
| CN=Root YR,O=ISRG,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | RSA 4096 | SHA256-RSA | f24b6d17f9d9ad7cb1c9fea78782699f |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of sync.day. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| day. | present | 41746 | 8 | Verified |
| sync.day. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=63072000 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://sync.day/mcp/mcp | Verified | 200 | |
| http (plaintext) | http://sync.day/mcp/mcp | HTTPS enforced | 308 | https://sync.day/mcp/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
create_event Create event ~409
Create a sync.day availability poll and get its share link. Candidate days run from startDate to endDate (inclusive; or give days instead). Each day offers candidate START times from hourFrom, every startStepMinutes, as long as start + durationMinutes <= hourTo. Returns slug, public url (share this), adminUrl and adminKey (keep private; needed for update_event / remove_participant). Example: 周六周日下午聚餐 3 小时 -> {title:'周末聚餐', startDate:'2026-09-05', endDate:'2026-09-06', hourFrom:13, hourTo:18, durationMinutes:180, startStepMinutes:60}.
| Name | Type | Req | Description |
|---|---|---|---|
| days | integer | – | Number of consecutive days from startDate (1-21); alternative to endDate. |
| durationMinutes | – | yes | Event length in minutes. One of 30, 60, 90, 120, 180, 240, 480. |
| endDate | string | – | Last candidate day, inclusive, YYYY-MM-DD (same as startDate for a single day; at most 21 days). Give this or days; endDate wins when both are set. |
| hourFrom | integer | yes | Earliest hour of each day (0-23). e.g. 9 |
| hourTo | integer | yes | End of each day's window, exclusive (1-24), must be > hourFrom. e.g. 22 |
| question | string | – | Optional prompt shown to participants, max 200 chars. e.g. 哪天晚上有空？ |
| startDate | string | yes | First candidate day, YYYY-MM-DD. e.g. 2026-09-05 |
| startStepMinutes | – | – | Gap between candidate start times in minutes: 30 or 60 (default 60). |
| title | string | yes | Event name, max 60 chars. e.g. 周末聚餐, Team sync |
No output schema declared.
No examples provided.
decide_time Decide the time ~125
Organiser only: settle on a start time (locks availability picking and voting; the page shows 已定). Pass start=null to reopen. Requires the adminKey from create_event.
| Name | Type | Req | Description |
|---|---|---|---|
| adminKey | string | yes | Organiser key returned by create_event (the ?key= part of adminUrl). |
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
| start | – | yes | A candidate start key of the event (normally one of voteOptions), or null to reopen. |
No output schema declared.
No examples provided.
get_event Get event ~114
Read an event: settings, every candidate start key per day (startOptions), who has answered (participants with their start keys; names may repeat), the top 10 start times by head-count (ranked), the starts EVERYONE with picks can make with their votes (voteOptions), each person's vote (votes) and decidedStart. No key needed.
| Name | Type | Req | Description |
|---|---|---|---|
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
No output schema declared.
No examples provided.
parse_event_text Parse event text ~109
Turn a natural-language sentence (Chinese works best) into create_event input using sync.day's AI parser. Does NOT create anything; review the result, then call create_event. Example: '下周六或周日下午聚餐，大概 3 小时'.
| Name | Type | Req | Description |
|---|---|---|---|
| text | string | yes | One sentence describing the event, max 300 chars. |
| today | string | – | Reference date for relative words like 明天/下周, YYYY-MM-DD. Defaults to today in Asia/Shanghai. |
No output schema declared.
No examples provided.
remove_participant Remove participant ~112
Organiser only: remove one participant by name (the oldest row with that name when it repeats), together with their vote. Requires the adminKey from create_event.
| Name | Type | Req | Description |
|---|---|---|---|
| adminKey | string | yes | Organiser key returned by create_event (the ?key= part of adminUrl). |
| name | string | yes | Exact participant name to remove. |
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
No output schema declared.
No examples provided.
submit_availability Submit availability ~267
Save (or replace) one person's availability: the candidate start keys they can make, from get_event.startOptions. The person is identified by `identity`, not by name: the same identity later overwrites the same row (and can rename it), a different identity with the same name is a second participant. Keys outside the event's start options are rejected. Returns the updated ranking.
| Name | Type | Req | Description |
|---|---|---|---|
| identity | string | yes | Random secret for this person that you generate and keep per person, 16-256 chars (e.g. 32 hex chars; NOT a plain user id or name, since anyone who guesses it can act as them). Same identity = same p… |
| name | string | yes | Display name, 1-20 chars, may repeat. e.g. 小明 |
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
| starts | array | yes | Start keys like 2026-09-05T14:00. Empty array clears this person's picks. |
No output schema declared.
No examples provided.
update_event Update event ~367
Organiser only: change any event settings (same fields and rules as create_event; omitted fields keep their current value; endDate wins over days). Existing picks are kept; those no longer valid starts are just hidden.
| Name | Type | Req | Description |
|---|---|---|---|
| adminKey | string | yes | Organiser key returned by create_event (the ?key= part of adminUrl). |
| days | integer | – | Number of consecutive days from startDate (1-21); alternative to endDate. |
| durationMinutes | – | – | Event length in minutes. One of 30, 60, 90, 120, 180, 240, 480. |
| endDate | string | – | Last candidate day, inclusive, YYYY-MM-DD (same as startDate for a single day; at most 21 days). Give this or days; endDate wins when both are set. |
| hourFrom | integer | – | Earliest hour of each day (0-23). e.g. 9 |
| hourTo | integer | – | End of each day's window, exclusive (1-24), must be > hourFrom. e.g. 22 |
| question | string | – | Optional prompt shown to participants, max 200 chars. e.g. 哪天晚上有空？ |
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
| startDate | string | – | First candidate day, YYYY-MM-DD. e.g. 2026-09-05 |
| startStepMinutes | – | – | Gap between candidate start times in minutes: 30 or 60 (default 60). |
| title | string | – | Event name, max 60 chars. e.g. 周末聚餐, Team sync |
No output schema declared.
No examples provided.
vote_time Approve start times ~325
Approval voting: set every start one person accepts (replaces their earlier approvals; an empty list clears them). The voter is the `identity` used in submit_availability and must have at least one start saved. Only keys listed in get_event.voteOptions are accepted; the error lists the current options otherwise. Rejected once the organiser decided. Example: {slug:'calm-otter-4821', identity:'3f9a1c77b2e04d5e8a61f0c9d2b7e415', starts:['2026-09-05T15:00','2026-09-06T10:00']}. `start` is shorthand for a single-item `starts`.
| Name | Type | Req | Description |
|---|---|---|---|
| identity | string | yes | Random secret for this person that you generate and keep per person, 16-256 chars (e.g. 32 hex chars; NOT a plain user id or name, since anyone who guesses it can act as them). Same identity = same p… |
| slug | string | yes | Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821) |
| start | string | – | Shorthand for starts: [start] |
| starts | array | – | All start keys this person accepts (from get_event.voteOptions); [] clears their approvals |
No output schema declared.
No examples provided.
How do I install the io.github.syncday-app/sync-day MCP server?
io.github.syncday-app/sync-day is a hosted endpoint at https://sync.day/mcp/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · sync.day
claude mcp add --transport http syncday-app-sync-day 'https://sync.day/mcp/mcp'
What is the io.github.syncday-app/sync-day MCP server?
io.github.syncday-app/sync-day is an MCP server listed in the public MCP registry as io.github.syncday-app/sync-day. Free no-signup group scheduling; share a link and rank times by who's free. This page covers its hosted endpoint (https://sync.day/mcp/mcp).
Is the io.github.syncday-app/sync-day MCP server safe to use?
io.github.syncday-app/sync-day scores 79 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the io.github.syncday-app/sync-day MCP server expose?
io.github.syncday-app/sync-day exposes 8 tools: create_event, parse_event_text, get_event, submit_availability, remove_participant, and 3 more. Their descriptions and schemas cost roughly 1,828 tokens of context every time the server is loaded.
Does the io.github.syncday-app/sync-day MCP server require authentication?
No. We connected to io.github.syncday-app/sync-day without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the io.github.syncday-app/sync-day MCP server still maintained?
io.github.syncday-app/sync-day is still listed as active in the MCP registry. We last reached this channel on 4 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.